The 3/4" Wilkins Model 350 double check assemblies began production in 2004 and are currently still being produced. They feature a bronze carriage that holds a plastic body which houses the check assemblies. The plastic housing rests into the bronze carriage and is locked in with a wedge system. The device is an inline module check design. In 2010, Wilkins introduced the 350XL, which is the lead free version. A blowout fitting is available for simple winterization. No special tools are required for servicing.